Carbon corrosion of proton exchange membrane fuel cell catalyst layers studied by scanning transmission X-ray microscopy

Hitchcock, Adam P.; Berejnov, Viatcheslav; Lee, Vincent; West, Marcia; Colbow, Vesna; Dutta, Monica; Wessel, Silvia

doi:10.1016/j.jpowsour.2014.04.119

Cited by 74 publications

(78 citation statements)

References 24 publications

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“…For example, CNT is a material with high electrical conductivity but has a limiting active surface area matched to the commercial Vulcan‐XC due to poor pore development. The structure and composition of the catalyst support layer and operating condition are important points to consider because of the causes of carbon corrosion rate in electrode . The Pt ratios of carbon material support have a different effect on ECSA degradation.…”

Section: Limitations Related To Carbon Materialsmentioning

confidence: 99%

Allotrope carbon materials in thermal interface materials and fuel cell applications: A review

2019

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Summary The performance of allotrope carbon materials has been explored because of their superior properties in energy system applications. This review provides an understanding of the current work focusing on the applications of selected carbon materials in important energy systems, focus on thermal interface materials (TIMs), and fuel cell applications. This article begins with the introduction of TIMs and fuel cell in general working principle and presents details on carbon materials. The discussion focuses on updates from the latest research work and addresses current challenges and opportunities for research toward TIMs and fuel cell applications. The optimum performance of TIMs was seen when thermal conductivity achieved at a maximum of 3000 W (m K)−1 by using vertically aligned carbon nanotubes (CNTs) and a minimum internal thermal resistance of 0.3 mm2 K W−1. Meanwhile for fuel cell, the platinum/CNTs catalyst applied proton exchange membrane fuel cell achieved high power density of 661 mW cm−2 in the presence of Nafion electrolyte membrane. This review provides insights for scientists about the use of carbon materials, especially in energy system applications.

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Section: Limitations Related To Carbon Materialsmentioning

confidence: 99%

Allotrope carbon materials in thermal interface materials and fuel cell applications: A review

2019

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“…Figure 10b is a projection of the carbon fiber, Pt and Teflon™ fiber extracted from a reconstruction of a tomographic data set consisting of 40 angle measurements (-80 o to +80 o , every 4 o ) with images at 4 photon energies (278.0, 285.1, 684.0, 693.3 eV) measured at each angle. The transmission images at each angle were aligned and converted to quantitative Pt (from the OD 278 image, corrected for F-absorption [9]), carbon (OD 285.2 -OD 278 ) and fluorine (OD 693.3 -OD 684 ) maps using aXis2000. The maps at the full set of angles were then aligned and reconstructed using the sequential iterative reconstruction tomography (SIRT) method with 200 iterations using ImodJ [32], then rendered using Amira.…”

Section: D Chemical Mappingmentioning

confidence: 99%

“…These include development of dose-and time-efficient methods for quantitative mapping of ionomer in microtomed sections of membrane electrode assemblies [3,4]; in situ studies of effects of hydration at ambient temperature [5]; and 3D mapping of chemical species using multi-photon energy spectro-tomography [6]. STXM methods have been applied to studies of the role of the Pt-precursor on Pt degradation chemistry [7,8]; the fate of the PFSA ionomer during degradation by carbon corrosion [9]; ink-jet printed catalyst layers [10]; and the role of the perylene support in fabrication, assembly and degradation of alternative, nanostructured thin film catalysts [11,12]. These soft X-ray microscopy methods provide higher spatial resolution and detailed chemical speciation, and thus they complement hard X-ray microscopy approaches which are being used for in situ and operando studies of PEM-FC systems in both lab [13] and synchrotron [14][15][16] microscopes, as well as non-imaging synchrotron-based spectroscopic methods [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

Hitchcock

Lee

et al. 2016

AIP Conference Proceedings

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“…Potential cycling could lead to a successive oxidation/ reduction of surface groups present at the carbon support and other defect sites. At these sites carbon corrosion and platinum particle degradation take place simultaneously 33,35,59 whereas the ionomer from the polymer electrolyte seems to remain stable. 59 Fuel starvation conditions.-Fuel starvation conditions occur at very high fuel utilization, start/ stop conditions and purging the anode with air.…”

Section: F154mentioning

confidence: 99%

Accelerated Degradation of High-Temperature Polymer Electrolyte Fuel Cells: Discussion and Empirical Modeling

Reimer

Schumacher

Lehnert

2014

J. Electrochem. Soc.

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Accelerated stress tests are commonly applied in order to obtain a prediction of fuel cell life time within a short testing period. The stress test in this work considers a fuel cell which is constantly under load with frequent periods of very high current. Four different cells were operated each with a specific load profile. As a result severe performance degradation was observed in the region of high current densities. A short overview over the phenomena which may contribute to this specific fuel cell degradation is compiled from literature. Based on this overview major degradation modes are identified and combined with a simple polarization curve model. The modeling results allow for two different interpretations. Carbon corrosion reactions can explain the observed effects if cell voltage is assumed as the driving force for degradation. A better fit was obtained by using the overall heat flux as degradation criterion. In this case an increase in local temperature could lead to redistribution and loss of phosphoric acid from the MEA. The expected lifetime of a polymer electrolyte fuel cell (PEFC) ranges from 5 000 h for mobile application to 40 000 h for stationary application.1,2 In order to gain information about time dependent degradation in advance accelerated test protocols are used.3,4 Depending on the design of these tests valuable information about the nature of the main degradation mode under the applied operation conditions can be obtained. Despite the difference in operation conditions for PEFC, HT-PEFC and PAFC the structure and material of the electrodes are almost the same. Consequently, observed degradation phenomena show strong similarities.5 A good description of these phenomena can be found in several review papers 6-13 as well as in at least four books 1,2,14,15 where recent experimental facts and interpretations are summarized. A compact description can also be found in a recent review paper on modeling transport phenomena in PEFCs. 16 The purpose of this paper is to present the results of a specific accelerated degradation test for high temperature polymer electrolyte fuel cells (HT-PEFC) with phosphoric acid doped polybenzimidazole (PBI/H 3 PO 4 ) membranes. The fuel cell is constantly under load with frequent periods of very high current. In order to accelerate degradation effects the fuel cell is operated beyond it's point of maximum power. A simple polarization curve model is used as starting point for the analysis of data. Based on this first analysis a degradation model is proposed which allows for a straightforward physical interpretation. The complexity of degradation effects which occur simultaneousy usually leads to models which either resolve a specific mechanism in depth or describe more general effects. This paper aims at general effects which requires a broader understanding of degradation. In the following it is attempted to provide an overview over the phenomena which may contribute to fuel cell degradation. Based on this overview major degradation modes are identified and ...

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Carbon corrosion of proton exchange membrane fuel cell catalyst layers studied by scanning transmission X-ray microscopy

Cited by 74 publications

References 24 publications

Allotrope carbon materials in thermal interface materials and fuel cell applications: A review

Allotrope carbon materials in thermal interface materials and fuel cell applications: A review

Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

Accelerated Degradation of High-Temperature Polymer Electrolyte Fuel Cells: Discussion and Empirical Modeling

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